1. Field of the Invention:
The present invention generally relates to a method and a device for dynamically accelerating an analog-to-digital converter (ADC) and, more particularly, to a method and a device capable of detecting the sampling frequency and controlling the maximum conversion rate so as to dynamically accelerate the ADC.
2. Description of the Prior Art:
The analog-to-digital converter (ADC) is required for a liquid crystal display (LCD) to convert analog video signals into digital video signals, which are then output to a scaler in the LCD to accommodate the different format of the input video signal and the display.
Please refer to FIG. 1, which is a schematic diagram showing an ADC receiving an analog video signal. The ADC 110 converts and samples the analog video signal 115 so as to output a digital signal 117. The sampling frequency at which the ADC 110 samples the analog video signal 115 is determined by a clock signal 130. The clock signal 130 is generated by a phase-locked loop (PLL) 120 receiving a horizontal synchronization (H-sync) signal 135 in the LCD. The frequency of the H-sync signal 135 is equal to the horizontal scanning frequency of the LCD. The maximum conversion rate of the ADC 110 is a figure of merit when it comes to the performance of the ADC 110.
Generally, the maximum conversion rate of the ADC 110 has to be larger than or equal to the sampling frequency when the ADC 110 performs analog-to-digital conversion on the analog signal 115 such that the analog signal 115 can be converted into the digital signal 117. However, in some cases, when the resolution of the LCD is so high that the maximum conversion rate of the ADC 110 may be smaller than the sampling frequency, the LCD may suffer unsatisfactory quality. On the other hand, if the ADC 110 operates at the maximum conversion rate, it may result in poor ADC efficiency when the resolution of the LCD is low.
Therefore, there is need in providing a method and a device for dynamically accelerating an analog-to-digital converter (ADC), capable of detecting the sampling frequency and controlling the maximum conversion rate so as to dynamically accelerate the ADC.